# Tag Info

25

No. Not too unprotected, as you put it. There are several misconceptions that I find common about the JWST, that need to be addressed: JWST primary mirror elements are not made of glass and do not shatter on impact It's primary hexagon mirror elements are made out of Beryllium powder pressed into blocks, that were later cut in half to create two mirror ...

17

There was a design requirement (PDF, page 30) for a "probability of no penetration" of 95% for 2 years. The Space Debris Handbook (PDF, page 137) indicates the main risk was considered to be a light leak in the aft shroud. I haven't been able to find any specifics on construction details that ensure this. Specifically, I haven't found any mention of ...

8

This is an incredibly complex problem, so the only way I can think of usefully answering your question is by referring you to NASA's Micrometeoroid and Orbital Debris (MMOD) Shield Ballistic Limit Analysis Program and its documentation (PDF). This software complements the NASA's BUMPER-II risk assessment software package that was used for the Orion project (...

8

Essentially, they just accept the risk. The suit is strong enough to withstand strikes from those micrometeoroids and pieces of orbital debris most likely to hit it, and it's small enough (and EVAs are short enough) that larger, more damaging strikes are quite unlikely. The meteoroid and debris environments are only really understood in a broad average ...

7

From Wikipedia: The telescope will circle about the L2 point in a halo orbit, which will be inclined with respect to the ecliptic, have a radius of approximately 800,000 km (500,000 mi), and take about half a year to complete. A sphere with a radius of 800,000 km has a surface of about 2 trillion square km. If we assume a million small bodies of detectable ...

7

Hypervelocity impacts on the space shuttle Orbiters were analyzed over the years to determine their origin. After the post-flight inspection is completed, JSC personnel analyze samples extracted from the impact sites using a scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometers (EDXA). ...

6

Radiation As you have rightly noted, a long cylinder pointing end on to the radiation source (probably the sun, especially during periods of high activity), can be shielded by a smaller, and thus lighter, shield. On the other hand if you need shielding facing all directions, then a sphere is a better choice. (Micro-)meteorites The spaceship is moving ...

5

The answer to this question has changed a few days ago. Cygnus NG-13 brought a Voxa Mochii suitcase-sized scanning electron microscope to the ISS in February 2020. See also GeekWire's From the garage to the space station: Voxa’s Mochii electron microscope will be flying high Having an electron microscope aboard the station — and having it hooked up for ...

5

In general, we prefer to return samples to Earth for analysis. There are many benefits: no need to haul instrumentation into orbit, plenty of storage/time/personnel/equipment for analysis, and easier to modify or expand experiments. When instrumentation is brought into space, it typically is for one of the following justifications: It is measuring ...

5

Source: https://www.nasa.gov/feature/goddard/2017/camera-on-nasas-lunar-orbiter-survived-2014-meteoroid-hit The above image is from one of the Narrow Angle Cameras on NASA’s Lunar Reconnaissance Orbiter. The very top of the image is clear. The rest shows jagged artifacts. Unlike the digital cameras one can buy in a store, the Narrow Angle Cameras are ...

4

A History of Micrometeoroid and Orbital Debris Impacts On The Space Shuttle lists the "top 20" strikes on space shuttle windows and radiators from 1992 to 2000; most of them are from debris but 4 appear to be from meteoroids. The biggest meteoroid hit appears to be a 5mm hole in a radiator from an 0.7mm meteoroid.

4

in Wikipedia I see eighteen discoveries by WIND but not that particular one... Yes, I have not had a chance to update the list of Wind discoveries for quite a while but plan to do so soon. ...while the STEREO spacecraft had a cluster of instruments called "IMPACT" the Wikipedia article doesn't mention the detection of dust impacts... The IMPACT ...

4

Dennis Wingo and I had an argument over this. Wingo argues asteroid impacts have left rich ore deposits on the moon. My response (which he did not like) was citing Barringer's disastrous effort to mine Barringer Crater in Arizona. Barringer was correct that the impactor was metallic. But the impact scattered the ore far and wide leaving it too diluted to be ...

4

Interstellar travel typically involves much higher velocities than current probes achieve. Depending on how long you are willing to allow the mission to take, you need velocities of a decent fraction of the speed of light. At that speed, anything you collide with, even the smallest speck of dust is quite dangerous. For instance at $0.1c$ (40 years to the ...

3

It's a risk. The danger has been calculated as follows: We computed the risk for a peak year of EVA activity, assumed by NASA to consist of 624 hours of EVA exposure. For that time period, we found that, the probability of a fatality is about 1.4x10-3 without shielding and 1.1x10-3 per 624 hours of EVA with shielding. Currently there is no shielding....

3

One should consider vectors of the items in question and allow that shape of the ship will have little impact on an impact. A good comparison is a vehicle traveling on a roadway. As it approaches an intersection with a green light, traveling at high speed, another vehicle disregards its red light and collides with the first vehicle. The shape of the first ...

3

Judging by the amount of rock vaporized in underground nuke tests, and the size of an average asteroid, todays nuclear weapons are easily capable of vaporizing all but the most massive of asteroids. The largest nuclear detonation by the US was Castle Bravo at 15Mt. This created a crater 2km in diameter and 75m deep. Thats 3.1x10^8 cubic meters. But thats a ...

3

As for the first part: Nukes have one great advantage over any other scheme that has been proposed. Every other suggested system requires matching orbits with the target before you can attempt to move it. So long as your guidance system is good enough a nuke doesn't need this. Your target is closing on the Earth at 10 km/sec, you have to fly out there, ...

3

If you have enough warning, there are more gentle and much more predictable approaches than using a nuke. If you don't have enough warning, then you're probably only going to get one shot at it, so you definitely don't want the unpredictability of a nuke imparting unknown velocities to unknown size pieces, only one of which would need to be large enough to ...

2

The ISS orbital debris threat is worst about thirty degrees to the left and right of the velocity vector in the local horizontal plane (see page 9 of the pdf linked here). At the ISS orbit, pretty much all collisional trajectories are due to differences in orbital plane. The ISS meteoroid environment is almost completely shadowed in the nadir direction, ...

2

Meteroides are on hyperbolic trajectories relative to earth. It is unlikely to encounter such an object coming from the deck-side, because earth masks most of the possible inbound trajectories and even if if misses the ground, the athmosphere would slow it and probably break it into pieces. Space debris is on elliptical orbits. Since most missions start in ...

2

Both the Rosetta mission, and the Mars Phoenix Lander had Atomic Force Microscopes aboard. These use a very sharp tip and sensitive force measurement to detect the interaction between the tip and the surface of the desired object. They generally fall into the SPM category you mentioned. The Rosetta instrument was used to examine comet and intrasolar dust, ...

2

Current spacecraft outside Earth orbit have little or no protection. they have no sensors that can detect small objects, and we can't detect small objects (say, less than 100 m in diameter) from Earth either they don't carry enough fuel to make course corrections quickly enough to avoid an object their structure is not built to withstand impacts from ...

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